Make GetRootWindow() return a Window instead of a RootWindow.

ash/wm/workspace/phantom_window_controller.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ASH_WM_WORKSPACE_PHANTOM_WINDOW_CONTROLLER_H_
 #define ASH_WM_WORKSPACE_PHANTOM_WINDOW_CONTROLLER_H_
 
 #include "ash/ash_export.h"
 #include "base/basictypes.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/gfx/animation/animation_delegate.h"
 #include "ui/gfx/rect.h"
 
 namespace aura {
-class RootWindow;
 class Window;
 }
 
 namespace gfx {
 class SlideAnimation;
 }
 
 namespace views {
 class Widget;
 }
@@ skipping 31 matching lines @@
   }
 
   // gfx::AnimationDelegate overrides:
   virtual void AnimationProgressed(const gfx::Animation* animation) OVERRIDE;
 
  private:
   FRIEND_TEST_ALL_PREFIXES(WorkspaceWindowResizerTest, PhantomWindowShow);
 
   // Creates, shows and returns a phantom widget at |bounds|
   // with kShellWindowId_ShelfContainer in |root_window| as a parent.
-  views::Widget* CreatePhantomWidget(aura::RootWindow* root_window,
+  views::Widget* CreatePhantomWidget(aura::Window* root_window,
                                      const gfx::Rect& bounds_in_screen);
 
   // Window the phantom is placed beneath.
   aura::Window* window_;
 
   // If set, the phantom window should get stacked below this window.
   aura::Window* phantom_below_window_;
 
   // Initially the bounds of |window_| (in screen coordinates).
   // Each time Show() is invoked |start_bounds_| is then reset to the bounds of
@@ skipping 16 matching lines @@
   // Used to transition the bounds.
   scoped_ptr<gfx::SlideAnimation> animation_;
 
   DISALLOW_COPY_AND_ASSIGN(PhantomWindowController);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_WM_WORKSPACE_PHANTOM_WINDOW_CONTROLLER_H_